Within the ends of axons of a neuron are _____ known as neurotransmitters

According to the article For Better or Worse concerning marital satisfaction in middle aged adults, in the main study in the article four groups were composed based on the internality or externality of husbands and of wives

Where "I" and "E" stand for the locus of control for individuals within a pair, the most satisfied group was the ___ group: (a) I/I (b) I/E (c) E/I (d) E/E

How much of our brain do we use?

a) more of the right than the left b) more of the left than the right c) about 10% d) 100%